html {
    /* 定义颜色变量 */
    --brand-green: #076448;
    --dark-green: #099268;
    --medium-green: #20c997;
    --text-color: #212529;
    --gray: #868e96;
    --light-gray: #f1f3f5;
    --extra-light-gray: #f8f9fa;
    --white: #fff;

    box-sizing: border-box;
    color: var(--text-color);
}

*, *::before,*::after {
    box-sizing: inherit;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.4;
    background-color: var(--extra-light-gray);
}

h1,h2,h3,h4 {
    font-family: Georgia, 'Times New Roman', Times, serif;
}

a {
    color: var(--medium-green);
}

a:visited {
    /* color: var(--brand-green); */
}

a:hover {
    color: var(--brand-green);
}

a:avtive {

}

p {
    margin-top: 1.5em;
    margin-bottom: 1.5em;
}

.nav-container {
    background-color: var(--medium-green);
}

.nav-container__inner {
    display: flex;
    justify-content: space-between;
    max-width: 1080px;
    margin: 0 auto;
    padding: .625em 0;
}

.home-link {
    color: var(--text-color);
    font-size: 1.6rem;
    font-family: Georgia, 'Times New Roman', Times, serif;
    font-weight: bold;
    text-decoration: none;
}

.top-nav {
    display: flex;
    list-style-type: none;
    margin: 0;
}

.top-nav > li + li {
    margin-left: .625em;
}

.top-nav a{
    display: block;
    padding: .3em 1.25em;
    color: var(--white);
    background-color: var(--brand-green);
    text-decoration: none;
    border-radius: 3px;
}

.top-nav a:hover {
    background-color: var(--dark-green);
}

.top-nav__featured > a {
    color: var(--brand-green);
    background-color: var(--white);
}

.top-nav__featured > a:hover {
    color: var(--medium-green);
    background-color: var(--white);
}

/* 主体和按钮 */
.hero {
    background: url(https://img1.baidu.com/it/u=847956157,2750448390&fm=253&fmt=auto&app=138&f=JPEG?w=800&h=500) no-repeat;
    background-size: cover;
    margin-bottom: 2.5rem;
}

.hero__inner {
    max-width: 1080px;
    margin: 0 auto;
    padding: 5.5625em 12.5em 12.5em 0;
    text-align: right;
}

.hero h2 {
    font-size: 1.95rem;
    margin-top: 0;
    margin-bottom: .625rem;
}

.button {
    display: inline-block;
    padding: .4em 1em;
    color: var(--brand-green);
    border: 2px solid var(--brand-green);
    border-radius: .2em;
    text-decoration: none;
    font-size: 1rem;
}

.button:hover {
    background-color: var(--dark-green);
    color: var(--white);
}

.button__cta {
    padding: .6em 1em;
    background-color: var(--brand-green);
    color: var(--white);
    border: none;
}

.container {
    margin: 0 auto;
    max-width: 1080px;
}

.tile-row {
    display: flex;
}

.tile-row > * {
    flex: 1;
}

.tile-row > * + * {
    margin-left: 1.5625em;
}

.tile {
    background-color: var(--white);
    border-radius: .3em;
}

.tile > h4 {
    margin-bottom: 1.5em;
}

.page-footer {
    margin-top: 3em;
    padding: 1em 0;
    background-color: var(--light-gray);
    color: var(--gary);
}

.page-footer__inner {
    margin: 0 auto;
    max-width: 1080px;
    text-align: center;
    font-size: .8rem;
}

.tag-list {
    list-style: none;
    padding-left: 0;
}

.tag-list > li {
    display: inline;
    padding: .3rem .5rem;
    font-size: .8rem;
    border-radius: .2rem;
    background-color: var(--light-gray);
    line-height: 2.6;
}